High vacuum gate valves are known in the prior art. Such valves are typically used in severe environments, such as the environments experienced in fabrication processes of integrated circuit semiconductors, for example. Low pressure chemical vapor deposition processes, such as sputtering, plasma, and the like, also require high vacuum conditions in conduits, joints and valves. High vacuum joints and valves are typically formed of corrosion resistant materials such as stainless steel, and they may be required to operate at very high temperatures.
High vacuum gate valves typically provide for actuation from the ambient, and preferably with no loss of vacuum level. The sealing surface of a gate of a high vacuum valve is typically an annular, rectangular or circular surface and gasket that closes with considerable force upon a complementary seating surface during operation.
Prior art control mechanisms for the operation of high vacuum gate valves have typically included a large number of moving parts, for example a complex linkage assembly and locking device attached to the gate portion of the valve, to transfer the linear displacement force applied to the carriage assembly of the gate and thereby force the sealing surface of the gate into contact with the seat of the valve. One such prior art device employing a linkage assembly for operation of a gate valve is disclosed in U.S. Pat. No. 4,681,329, owned by the Assignee of the present invention. The linkage assembly in the 329' patent enables the sealing surface to pivot into contact with the seat of the valve, and a stop dog mechanism maintains the seal.
During fabrication processes of integrated circuit semiconductors, for example, semiconductor wafers typically are conveyed from the ambient through a high vacuum gate valve into a high pressure vacuum chamber. The high vacuum gate valve opens and closes as the semiconductor wafers pass through into the vacuum chamber.
Vibrations are typically generated in a high cycle, high vacuum gate valve during opening/closing operations. These vibrations typically result from the substantial number of linked moving parts required to operate the valve with the force necessary to effect and maintain a vacuum seal. Such vibrations may be transferred to the extremely delicate semiconductor wafers with adverse consequences.
An unsolved need exists for a simplified, yet highly effective LVHC high vacuum gate valve.